Butter vs Margarine: What's the Real Difference?

Have you ever wondered what makes butter and margarine different? A food scientist is sharing the science behind these two popular kitchen staples. Both spreads look similar and taste good on toast, but they are made very differently. Understanding how they work can help you become a better cook.

Both butter and margarine are called emulsions. This means they are mixtures of tiny water drops spread through fat. The fat is made mostly of triglycerides, which are the main type of fat we eat. Think of triglycerides like a backbone with three arms attached.

Butter's fatty acids are mainly saturated, which means they fit together neatly like straight puzzle pieces. This makes butter firm when it's cold and helps it trap air when mixed with sugar for baking. Margarine's fatty acids are mainly unsaturated, coming from plant oils. The double bonds between carbons kink the molecule so they cannot be as neatly arranged.

Butter is made by churning cream until fat globules break apart. The fat leaks out and forms grains of butter that separate from the watery buttermilk. You can actually make butter at home by whipping heavy cream in a mixer. The golden color in butter comes from beta-carotene, an orange pigment from grass that cows eat.

Margarine starts as liquid plant oils that are made solid through a chemical process. This rearranges the fat molecules without adding unhealthy trans fats. Since margarine is naturally colorless, makers add synthetic beta-carotene to make it look like butter. They also add flavors and preservatives to copy butter's taste.

The chemistry differences create different cooking results. When you heat butter, its proteins and milk sugar combine to create a brown color and nutty flavor. Margarine doesn't contain milk sugar, so it won't brown the same way. Both spreads work in most recipes, but knowing their differences helps you choose the right one.